HHRA Phase 4: Additional Data Collection and Probabilistic Risk Calculations (2008)

Human Health Reports, Reports

A report on the fourth step in detailed Human Health Risk Assessment for smelter-related metals, other than lead. This phase reevaluated risks from metals in the environment by incorporating new data for outdoor air, soil, outdoor and indoor dust, surface water, groundwater, beach sand, locally grown produce and locally caught fish. All data were screened against regulatory standards, some of which had changed since the previous phase in 2000. This phase therefore involved evaluation of peoples’ exposures to a broader suite of metals and under additional land use scenarios than had been considered in previous phases. For example, this phase evaluated other metals such as mercury (triggered by concentrations measured in fish) and thallium (triggered by concentrations measured in produce) and also assessed people’s potential exposures to river sediments at a downstream beach area and to soil/dust in an off-road vehicle use area.

The risk assessment in Phase 4 again employed prescribed methods from regulatory agencies in BC (or Canada or USA where not prescribed for BC) to estimate long-term exposures and risks to residential, commercial, recreational and agricultural land users. In addition, probabilistic risk calculation methods were employed for a more informative look at risks from arsenic and cadmium.

The overall conclusion of this comprehensive reevaluation was the same as in previous phases, i.e., that risks were low and that the potential concern to watch going forward was arsenic concentrations in outdoor air.